a) Field of the Invention
This invention relates to a new or improved arrangement for separating gas from liquids, and in particular relates to a new or improved gas separator. The gas separator disclosed herein is particularly although not exclusively intended for use with a downhole progressing cavity pump for removing gas from liquids extracted from subsurface formations, prior to the liquid entering the pump suction.
b) Description of the Prior Art
Progressing cavity pumps are volumetric type pumps so that the efficiency of the pump is reduced by whatever percentage of the pump volume is occupied by gas. Furthermore the stator of such a pump will usually have an elastomer covering and such elastomers can be damaged by gases such as carbon dioxide and hydrogen sulphide which are typically encountered in oil well bores. Progressing cavity pumps also rely for their lubrication and cooling on the liquid that is being pumped. If this liquid contains too high a content of gas, then the pump will not be properly lubricated and cooled. Where lubrication and/or cooling are insufficient, then the pump stator may experience accelerated wear, and furthermore the heat generated by friction between the rotor and the stator can cause the stator to be "cooked" or "burned" resulting in premature failure of the stator and the pump.